1. Field of the Invention
The present invention generally relates to apparatuses for applying granular and/or liquid materials to lawns and gardens. More particularly, this invention relates to a self-propelled spreader configured to broadcast both granular and liquid materials at multiple rates that are synchronized with multiple forward speeds of the spreader so that the materials are dispensed to achieve an approximately constant application rate per unit area regardless of which of the forward speeds the spreader is operating.
2. Description of the Prior Art
Lawn and garden maintenance often includes the application of dry (e.g., granular) and liquid materials, including seed, fertilizers, insecticides, herbicides and flingicides. While dry and liquid materials have been broadcast on lawns and gardens using separate equipment, U.S. Pat. No. 5,333,795 to Jessen (incorporated herein by reference) discloses a single spreader unit capable of simultaneously dispensing both liquid or granular materials. Jessen""s spreader unit includes a rotating platter for broadcasting granular materials and multiple spray nozzles for dispensing liquid materials. Though self-propelled to reduce the amount of effort required to apply materials to a lawn or garden, the spreader unit does not provide a platform by which the operator can ride on the unit. Even if so modified, there are circumstances in which the operator of the unit may prefer or be required to walk behind the spreader unit. To complete the application of material more quickly, it is generally typical that the maximum forward speed of a self-propelled spreader unit will be higher than the walking pace found comfortable by its operator, such that different forward speeds are required for the unit to operate under different conditions. Complicating this situation is the importance for the materials, and particularly fertilizers and herbicides that can harm grass and other desired vegetation if applied too heavily, to be applied at an approximately constant application rate per unit area, regardless of the forward speed of the spreader. Another complicating factor is the occasion when the material is to be applied to a relatively restricted or narrow area, necessitating that the extent to which the material is broadcast must be limited by the use of deflectors or by shutting off flow to the appropriate dispensers (e.g., nozzles). However, limiting the broadcast of the material should be done without increasing the application of material on the area being treated to avoid damage to vegetation within the treated area.
From the above, it can be seen that further improvements in lawn and garden spreaders would be desirable, and particularly a self-propelled spreader capable of uniformly applying a granular and/or liquid material on a lawn or other ground surface regardless of the speed of the spreader and regardless of the area of the ground surface being treated.
The present invention provides a self-propelled lawn and garden spreader that can be used to apply granular and/or liquid materials to both wide and narrow areas at a constant rate of application per unit area at different ground speeds, such as at a relatively high speed when the operator of the spreader is riding on the spreader, and at a relatively low speed when the operator is walking behind the spreader. The spreader generally includes a frame on which a suitable motor is mounted, wheels mounted to the frame with at least one of the wheels being driven by the motor, and means for controlling the ground speed of the spreader, including at least two forward speeds. The spreader further includes a material storage compartment mounted to the frame for containing a material. The material storage compartment has an outlet through which the material exits the material storage compartment and is delivered to a dispenser unit that broadcasts the material outwardly, including away from the sides of the frame. Finally, the spreader includes a device for controlling material flow from the material storage compartment to the dispenser unit. According to the invention, the material flow control device provides at least two flow rates of the material to the dispenser unit, in which the flow rates are synchronized with the at least two forward speeds of the spreader so that the spreader dispenses the material to achieve an approximately constant application rate per unit area at the at least two forward speeds.
In view of the above, it can be appreciated that the spreader of this invention can be used to perform at least two types of treatments, either separately or simultaneously. In a preferred embodiment, the material storage compartment includes at least one tank of liquid treatment material. Hoses define fluid paths that connect the tank to multiple frame-mounted nozzles, and valves enable the operator to selectively cause fluid to flow to one or more of the nozzles. A pressure control device is also provided to maintain a constant pressure within the tank and hoses, regardless of which nozzle or nozzles are selected by the operator. The excess flow generated by the material flow control device is bypassed back into the tank, providing mixing of the contents. The nozzles are preferably grouped into at least two sets, each with a right and left nozzle that when operated together preferably cover the entire broadcast width desired for the liquid treatment material. The nozzles of each set also preferably have different flow rate capacities that, through proper selection of the nozzles, produce a constant rate of application per unit area at different ground speeds.
Also in a preferred embodiment, the spreader includes at least one bin as a material storage compartment for a granular treatment material, and a dispenser for dispersing the granular material on the ground surface being treated. Also preferably included is a deflector that can be used to prevent the granular material from being dispersed to either side of the spreader at the discretion of the operator, and a device for controlling the flow of the granular material to provide multiple sets of at least two flow rates. The granular flow control device is calibrated so that the flow rates of each set enable the spreader to dispense the granular material at an approximately constant application rate per unit area at the different forward speeds of the spreader.
Other preferred features of the invention include configuring the spreader to have drive wheels on a front section that includes the frame, with a sulky equipped with wheels mounted to the frame as a rear section of the spreader. The sulky provides a platform on which the operator can ride. The front and rear sections of the spreader can be connected together by an articulating joint linkage that enables the sections to bend side to side laterally for steering, and to rotate radially. To provide a method for treating small, difficult to reach or remote areas of a lawn or garden, the spreader is also equipped with a flexible squeeze bottle that can be filled from the storage compartment on the spreader, and then hand-operated remote from the spreader. The bottle is preferably equipped with a nozzle body that prevents fluid from splashing directly out of the nozzle body when the bottle is held upright and shaken.
Other objects and advantages of this invention will be better appreciated from the following detailed description.